Method for forming a graphic image web

ABSTRACT

The present invention is a method for forming a graphic image web including a precursor image web combined with a congruent lenticular lens web to produce the illusion of three dimensionality in a visually perceptible image on the graphic image web. To produce this illusion of three dimensionality, an image field including an object is defined. The object is imagewise exposed onto a photographically sensitive element over a plurality of spatially disparate views through a lenticular lens having a prescribed optical geometry. Upon developing the latent image on said element, it is printed to form the precursor image web. The congruent lenticular lens web is then optically combined with the precursor image web to create the graphic image web having graphic information of photographically acceptable quality imparted with the illusion of three dimensionality.

TECHNICAL FIELD

The present invention relates generally to methods for creating theillusion of three dimensionality of a graphic image in printed web formand more particularly to a method for forming a graphic image web by alamination technique in which a precursor image web is combined with alenticular lens web to yield a graphic image having photographicallyacceptable quality.

BACKGROUND OF THE INVENTION

It is known in the art to fabricate generally planar display deviceswhich include an image sheet and a lenticular lens sheet which, incombination, give the image an appearance of three dimensionality. Thelenticular lens sheet and the image sheet must be aligned properly toavoid a distorted image. The components have heretofore been in sheetform because the process of combining them is usually manual to ensurenecessary registration.

The illusion of three dimensionality requires the image originally bemade with a special three dimensional or stereoscopic camera,photographing the desired object from a plurality of angularly displacedpositions. Such a camera typically uses a photosensitive film disposedbehind a lenticular screen. The lenticular screen is positioned adjacentthe photosensitive film so the focal point of each lenticule generallycoincides with the front surface of the film. Thus, the image of theobject is focused into a narrow image band which is exposed in the film.As the camera is shifted to the next angular position, the lenticularscreen is also shifted slightly. A subsequent picture image of theobject from the new angular position is then exposed into a separateimage band in the film adjacent the preceding image band. Each time thecamera is moved to a new angular position, the object is photographedand the image is exposed in the film as a similar, narrow image bandadjacent the previously formed image band, until a series of image bandsrepresenting different views of the object is created. To avoid overlapof image bands, the lenticular screen is only moved a distance equal tothe width of a single lenticule as the camera is moved through its fullangular range. This collection of image bands, which is formed under asingle lenticule, may be called an image element. Each image element isapproximately the width of a single lenticule and includes all of thecondensed views of the object.

Cameras of this type are disclosed in Stockbridge et al., U.S. Pat. No.3,380,360, issued Apr. 30, 1968 and Bonnet, U.S. Pat. No. 2,508,487,issued May 23, 1950. Both of those patents disclose three dimensional orstereoscopic cameras used to photograph objects from numerous angularpositions where the photograph taken at each position is exposed on afilm as a linear image band.

Once the object is photographed from the various positions, the film maybe developed the same as any other photographic film, but the resultingimage is a compilation of the numerous adjacent image bands. Each imageband represents the object from a given angle, albeit in a focused orcompressed form. This can provide the overall image with a somewhatdistorted look to the naked human eye. However, when the developed imageis combined with a lenticular screen or sheet having lenticules ofapproximately the same size and focal length as the lenticular sheetused to expose the film, the image becomes clear to the human eye asviewed through the screen.

The lenticular sheet must be placed over the image elements so the focalpoint of each lenticular lens coincides with the front surface of theimage sheet. The image will appear to be three-dimensional because theobserver is viewing the image through the lenticular sheet from aslightly different angle due to the lateral spacing between his eyes. Ineffect, this allows each eye to focus on a different image bandrepresenting different views of the photographed object from separateangles, thereby giving the viewer the illusion of a three dimensionalimage.

In the past, the lenticules and image elements Were relatively wide andeach lenticule had to be perfectly aligned over each image element toobtain a clearly defined three dimensional image. It has been difficultto obtain precise alignment and impossible to mass produce threedimensional images efficiently and economically. Typically, thelenticular sheet has been manually positioned over the image sheet andthen carefully adjusted to eliminate moire lines or interference. Thisis a time consuming, inefficient and expensive task.

Further difficulties exist in mass producing three dimensional imagesheets for use in publications such as magazines due to the size of thelenticules and the consequent thickness of the lenticular lens sheet.However, larger lenticules have longer focal lengths and necessitate athicker lens overlay so the focal point of the lenticule isapproximately adjacent the image elements on the image sheet. This, ofcourse, leads to a relatively thick composite sheet which is notsuitable for magazines or other printed media that require a thinnersheet dimension. Making the sheet sufficiently thin to be used inmagazines requires the lenticules to be extremely small thus making itmore difficult to form the lenticular lens sheet and properly align itwith the image sheet. The required precision has made the use ofefficient, high output machinery difficult.

It has long been desirable but unattainable to make both the image sheetand the lenticular lens sheet in web form and then combine them in webform at a rapid pace with precis registry to produce a finished producthaving photographilly acceptable quality. Standard printing methodscould then be used to reproduce the images in web form. Thoughtechniques have been developed for creating a lenticular lens in webform, and certain methods and devices have also been used in an attemptto combine an image web with a lenticular lens web, none of thesedevices is able to produce a thin flexible lenticular image web foreconomical use in the production of, for example, magazines, whilemaintaining the precision necessary to produce quality images having theillusion of three dimensionality without interference lines or distortedappearance.

In three patents to Conley, U.S. Pat. No. 4,420,502, issued Dec. 13,1983, U.S. Pat. No. 4,414,316, issued Nov. 8, 1983, and U.S. Pat. No.4,420,527, issued Dec. 13, 1983 an apparatus and method for making alenticular lens web are disclosed. A transparent base web is directedonto the surface of a first roll and advanced along an accurate patharound the first roll and then through a narrow gap disposed between thefirst roll nd a second roll. Before the transparent base web passesbetween the first and second rolls, a flowable uncured actnicradiation-curable thermosetting resin is directed onto the web behindthe narrow gap. The second roll includes grooves so that, as the resincovered web passes through the narrow gap and around the second roll,lenticular formations are made in the flowable resin. Ultravioletradiation is directed through the transparent base web and into theflowable resin layer while it remains in contact with the second roll.Thus the flowable resin is cured into a composite lenticular lens web.

Such a process can produce small, well defined lenticular lenses.However, the difficulty remains in properly laminating such a lenticularlens web with a corresponding image web in a manner that avoidsdistortion of the image. Typically, the lenticular lens web will stillneed to be cut in sheets and then carefully aligned by hand with acorresponding image sheet. It would be advantageous, and meet thelong-felt need summarized above, if such a lenticular lens web could beprecisely aligned and combined with the corresponding images while theimage sheet and lenticular lens sheet both remained in web form. Thiswould greatly increase the efficiency and volume of the finished webresulting in a very economical product.

Other patents disclose methods and devices for making lenticular lensproducts but none with the accuracy or precision that would allow thefinished product to be used in typical publications such as magazines.For instance, Jerothe et al., U.S. Pat. No. 3,264,164, issued Aug. 2,1966 discloses a device which makes a laminated, flexible fabric-likematerial having interesting characteristics of color and depth. However,precise accuracy is not necessary since one of the purposes of thepatented device is to produce images having a moire effect.Additionally, that approach merely uses colored lines and variouscolored shapes placed at different depths between cumulative flexiblesheets. In the Jerothe et al. device, a relatively thick sheet is usedfor the formation of the lenticular lens. The lenticular lens sheet islaminated with various films and then the resulting laminate passesbetween a pressure roll and a gravure roll where surface ribs orlenticular lens type ribs are formed by pressing the relatively thicklens forming sheet against the gravure roll. That device, however,cannot be accurately controlled to make extremely small accuratelenticular lenses in alignment with the image bands of an image web toyield photographically acceptable image quality.

Leach, U.S. Pat. No. 3,565,733, issued Feb. 23, 1971 discloses anapparatus for making a composite web from a paper web combined withmelted plastic. In Leach, a paper web, which can include an image, ispassed between a pressure roll and a coating roll and then around achilled embossing cylinder. A melted plastic is poured onto the coatingroll which brings the melted plastic into contact with the paper web.This combined paper web and melted plastic is immediately brought intocontact with the surface of the chilled embossing cylinder whichsolidifies the melted plastic leaving lenticular lens-type formations inthe plastic. A problem with the Leach apparatus is that it does notprovide for the precision alignment of the lenticular lens formationswith the image elements on the image web. This prevents the constantreplication of high quality images having the appearance of threedimensionality without distortion. Additionally, meltable plastic willnot retain its proper shape under the rigors of magazine use andshipping which can tend to place the lenticular lens formations underharsh conditions of pressure and heat. Once the lenticular lensesdegrade, the three dimensional effect is lost.

In Lemelson, U.S. Pat. No. 3,146,492, issued Sep. 1, 1964, an apparatusis disclosed which produces a multiple image sheet display on acontinuous basis. In Lemelson, an impressionable sheet is laminated witha plurality of sheets and then passed through a pair of rolls. One ofthe rolls is an embossing roll which creates lenticular formations in aface of the impressionable sheet. The apparatus is similar to thosementioned above in that it is difficult to form precision lenticules inthe solid web, without which an image of photographically acceptablequality cannot be reliably and repeatedly reproduced. Additionally,there is no way for the machine to provide precise alignment of theimage elements with the lenticules.

The present invention addresses the foregoing drawbacks involved inmaking a precision lenticular lens image web having three dimensionalimage characteristics with photographic quality.

SUMMARY OF THE INVENTION

The present invention provides a method for forming a graphic image webincluding a precursor image web combined with a congruent lenticularlens web to produce the illusion of three dimensionality in a visuallyperceptible image on the graphic image web. The method includes thesteps of defining an image field including an object to be viewed. Thisobject is then imagewise exposed onto a photographically sensitiveelement over a plurality of spatially disparate views through alenticular lens having a prescribed optical geometry. The latent imageis developed on the element and the developed image is printed to formthe precursor image web. The precursor image web and congruentlenticular lens web are optically combined to create the graphic imageweb having graphic information of photographically acceptable qualityimparted with the illusion of three dimensionality.

Additionally, the method provides for optically aligning the precursorimage web and the lenticular lens web during translation of both webs.The lenticular lens web includes a plurality of lenticules which arealigned with a plurality of image elements printed on the precursorimage web to impart graphic information of photographically acceptablequality with the illusion of three dimensionality. The photographicquality is facilitated by producing a lenticular lens web havingsufficient density of lenticules or by using a registration assembly tolaterally register the lenticular lens web with the precursor image web.

The invention provides for the illusion of three dimensionality in a twodimensional image. A person viewing the image on the precursor image webwill see what appears to be and what is a two dimensional image. Theimage is a collection of disparate condensed views of the object in theimage field as created through the lenticular lens of a stereoscopiccamera. After optically aligning the lenticular lens web over theprecursor image web, the individual viewing the two dimensional imagethrough the lenticular lens web will then see what appears to be a threedimensional object. This illusion of three dimensionality is created bythe optical configuration of the lenticular lens web which is disposedbetween the image contained on the precursor image web and the eyes ofthe individual.

BRIEF DESCRIPTION OF THE DRAWING

The invention will hereafter be described with reference to theaccompanying drawing, wherein like numerals denote like elements, and:

FIG. 1 is a schematic view of an object being exposed on photographicfilm through a lenticular sheet;

FIG. 2 is a front elevation view showing the formation of a graphicimage web by combining a precursor image web with a lenticular lens web;

FIG. 3 is a schematic perspective view showing the paths of travel ofthe precursor image web and the lenticular lens web as they arecombined;

FIG. 4 is a schematic side view of the relief cut roll which forms thelenticules in the lenticular lens web;

FIG. 5 is a schematic perspective view of a printing unit used in a weboffset press;

FIG. 6 is a schematic perspective view of a printing plate; and

FIG. 7 is a side view of the graphic image web which includes theprecursor image web combined with the lenticular lens web.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates generally to methods for producing aprinted graphic image having the illusion of three dimensionality and,more specifically, to methods for doing so in which the components areweb fed. The methods of the present invention are characterized by theirability to achieve a finished graphic image having photographicallyacceptable quality. While photographic quality of a printed graphicimage is a complex function of many production variables, ranging fromthe quality of the optical equipment, grain size and speed of the film,the quality and type of the printing equipment and selected printingprocess, it can be reduced to a more subjective level. Quality canconveniently be related to the ability of the observer to differentiatethe structure in the finished printed image; for example, the ability todistinguish quantitatively and qualitatively, facial features inportraits, (tree) limbs and foliage in panoramic vistas, and the like.When considered in the context of the present invention and the ensuingdescription, photographically acceptable quality thus refers to abenchmark measurement of clarity in the finished three-dimensional viewwhich is not materially, qualitatively distorted when compared to theprecursor image. This is unlike the prior art: methods capable ofadaptation to web-fed operation cannot achieve acceptable quality, thisis attainable only through labor intensive manual operation using sheetcomponents.

Referring now to the figures of the drawing, a method for forming agraphic image web will be described. As shown generally in FIG. 1, athree dimensional or stereoscopic camera 10 is used to create an imagewhich, when developed, will give the illusion of three dimensionalitywhen combined with a lenticular lens web having the requisite opticalgeometry. An image field 12 includes an object 14 which is to bephotographed. A single object 14 is used for illustrative purposes, butthis should not be deemed as limiting image field 12 to a single object.For instance, numerous objects could be included in the image field evento the extent that image field 12 is filled with various objects aswould be the case when photographing certain scenery. Often, however,when creating stereoscopic images it is desirable to have the object orobjects in a relatively narrow plane or lateral field of view to createan enhanced three dimensional effect.

Stereoscopic camera 10 is mounted on a device (not shown) which allowsit to be moved through a plurality of spatially disparate positions(shown in phantom) to obtain spatially distinct views of object 14. Eachof these spatially distinct views is exposed through a lenticular filmassembly 16 which includes a photographically sensitive element 18, suchas photographic film, combined with a superimposed lenticular lens 20.As light, reflected from object 14, enters camera 10 it passes throughlenticular lens 20 and is focused into narrow condensed bands exposingphotosensitive element 18 along narrow image bands.

In the preferred embodiment, lenticular lens 20 and photosensitiveelement s are relatively laterally movable. Photosensitive element 18 ispreferably mounted in a mechanism (not shown) which moves it inproportion to the movement of camera 10. Thus, as camera 10 moves fromone position to the next, photosensitive element 18 will move slightlyalong the length of lenticular lens 20 (shown in phantom). By movingelement 18, the light reflected from object 14 at each adjacent cameraposition is focused by lenticular lens 20 into narrow bands adjacent thenarrow image bands exposed on photosensitive element 18 at the previouscamera position. Object 14 is thereby imagewise exposed at differentlocations along photosensitive element 18 with each exposure locationcorresponding to one of the spatially distinct views of the objectobtained at one of the camera positions.

More particularly, lenticular lens 20 includes a plurality of lenticules22 each having a given, preferably similar, focal length depending onthe size and the curvature of the lenticules. When object 14 isphotographed, light reflected from object 14 enters camera 10 andstrikes lenticular lens 20. Each lenticule 22 focuses the light towardsits focal point. Preferably photosensitive element 18 is disposedapproximately in line with the focal points of the plurality oflenticules 22. This ensures that the light striking each lenticuleconverges into a narrow band at photosensitive element 18, creating aplurality of narrow condensed image bands 24 where the light focused byeach lenticule exposes element 18.

Stereoscopic camera 10 is then moved to an adjacent location which givesa spatially disparate or distinct view of object 14. As camera 10 ismoved to the next position, lenticular lens 20 is moved slightly withrespect to photosensitive element 18 so that this view of object 14 willbe focused on element 18 by lenticules 22 along narrow image bands 24adjacent the prior image bands 24. Preferably, as camera 10 is movedthrough its full range of positions, lenticular lens 20 is moved withrespect to photosensitive element 18 over a distance approximately equalto the width of one lenticule 22. This will ensure that the image bands24 created at each position of camera 10 will adequately expose theentire surface of photosensitive element 18 while preventing overlap ofthe image bands 24 formed under one lenticule with those formed underthe adjacent lenticule.

When photosensitive element 18 is completely exposed, it will include aplurality of image elements 26. Each image element 26 is ofapproximately the same width as the width of each lenticule and includesa plurality of image bands 24 representing the various spatiallydisparate views of object 14 taken from and corresponding to thedifferent positions of camera 10. In the most preferred embodiment,camera 10 is continuously moved through its range of positions with itsshutter held open. Simultaneously, lenticular lens 20 is continuouslymoved laterally with respect to photosensitive element 18 in an amountgenerally equal to the width of one lenticule. This provides foruninterrupted imagewise exposure of object 14 onto photosensitiveelement 18 so that there are no visually discernible breaks or gapsbetween image bands 24. Instead, image elements 26 each comprise thefocused composite of the spatially disparate views obtained when camera10 is moved through its range of motion while object 14 is continuouslyexposed along element 18.

If camera 10 is moved through a substantial range of positions, it ispreferably moved along an accurate path so that the distance betweenobject 14 and camera 10 remains constant. However, if the spatiallydisparate views of object 14 are created with minimal motion of camera10, then camera 10 can be moved along a straight line (i.e., a chord),as depicted in FIG. 1. This will not substantially affect the quality ofthe exposed latent three dimensional image on photosensitive element 18due to the slight difference between arc and chord length.

Following exposure of image elements 26 on photosensitive element 18,the latent image may be developed by normal methods used in developingphotographic film or other light sensitive emulsions. The developedimage is then printed on a web, referred to herein as a precursor imageweb, and replicated along the longitudinal length of the web usingconventional printing techniques. The web may be made of a variety ofmaterials including, for example, paper stock typically used forperiodical magazines. Image elements 26 are aligned generallylongitudinally with the web or, in other words, are aligned generally inthe machine direction. As discussed below, however, it is preferred thatthe image elements are disposed at a slight angle to the true machinedirection.

To create the illusion of three dimensionality, the precursor image webmust be optically combined with a lenticular lens web. The lenticules ofthe lenticular lens web are aligned with the image elements 26 so that aperson viewing the images on the precursor image web will perceive themas three dimensional. Forming the lenticular lens web and aligning itwith image elements 26 of the precursor image web is a precisionoperation performed by a web apparatus 30, shown generally in FIGS. 2and 3.

Web apparatus 30 is used to combine a precursor image web 34, includingimage elements 26, with a congruent lenticular lens (which may be leftblank, printed with ordinary two dimensional images, or printed withimage elements) web 36. Precursor image web 34 includes a back side 38and a three dimensional or 3-D printed side 40 which is placed inregistry with lenticular lens web 36.

In the preferred embodiment, shown generally in FIG. 2, a printed roll42 of precursor image web 34 is mounted in web apparatus 30. Precursorimage web 34 translates through a tensioner assembly 44 and then througha hood 46 where an adhesive 48, such as Morton International Blend 2359pressure sensitive adhesive, is applied. Precursor image web 34 alsomoves through an optional lateral registration assembly 50 which slavesprecursor image web 34 to lenticular lens web 36 so that they are inproper lateral or transverse registry when combined into graphic imageweb 32. Registration assembly 50 is optional because it has been foundthat in some applications lateral registration is not required.

Once precursor image web 34 and lenticular lens web 36 are properlyaligned, with or without the assistance of registration assembly 50, thewebs are pressed together between a base roll 52 and a biased pressureroll 54. Pressing web 34 and web 36 against base roll 52 allows adhesive48 to convert the two webs into single graphic image web 32.

In the preferred method for forming lenticular lens web 36, a flexibleweb 56 is combined with a flowable resin 58. Flowable resin 58 is formedinto a plurality of lenticules 60 and cured so that lenticules 60maintain their shape (see FIG. 4). Flexible web 56 preferably comprisesa transparent plastic material such as polyester, although, otherflexible relatively transparent materials could be used. A plastic roll62 of flexible web 56 is mounted in web apparatus 30 and supplies theflexible web 56 for combination with resin 58. When web apparatus 30 isoperating, web 56 moves through a tensioner assembly 64, around aplurality of guide rolls 68, and into a lenticule forming station 70(discussed below). After moving through forming station 70, flexible web56 moves around additional guide rolls 72 and then into contact withprecursor image web 34 at base roll 52.

As mentioned above, it is important that precursor image web 34 andlenticular lens web 36 are optically aligned when combined between baseroll 52 and biased pressure roll 54. Preferably, lenticules 60 haveapproximately the same cross-sectional dimensions and focal lengths aslenticules 22 of lenticular film assembly 16. This allows each lenticule60 to be linearly aligned with a single image element 26 on precursorimage web 34.

If lenticules 60 are large in cross-section, a better three dimensionaleffect is achieved by laterally aligning a single lenticule directlyover each image element 26. However, as lenticules 60 and thecorresponding image elements 26 are made narrower, it has beendetermined in accordance with the present invention that the need forprecise lateral alignment is reduced. A desirable three dimensionaleffect is produced by laminating precursor image web 34 to lenticularlens web 36 so that lenticules 60 are linearly aligned with imageelements 26. Proper linear alignment prevents distortion due to thecrisscrossing of lenticules 60 with image elements 26.

In the preferred embodiment, the number of lenticules 60 are at least100 per inch. At this density of lenticules, a desirable illusion ofthree dimensionality may be achieved without the use of lateralregistration assembly 50. In the most preferred embodiment, the densityof lenticules 60 is at least 300 per inch. This eliminates the need forregistration assembly 50 and also provides a short lenticule focallength to facilitate an extremely thin graphic image web 32.

In some cases, it may be desirable to alter the orientation oflenticules 60 with respect to image elements 26 to optically align themin a manner which produces moire patterns. However, it is generallydesirable to avoid any formation of moire patterns.

When lateral registration is required, registration assembly 50preferably comprises an ultrasonic guidance system 73. Ultrasonicguidance system 73 uses a pair of ultrasonic sensors 74 and 74', each ofwhich produce an ultrasonic beam which tracks the edge of the web it ismonitoring. Sensor 74 monitors an edge of precursor image web 34 whilesensor 74' monitors the edge of flexible web 56. The frequency of theultrasonic beam changes as it passes through different materials. Thus,the frequency of the beam passing through a web is different from thefrequency of the beam as it passes through atmosphere. The ultrasonicbeam either passes completely through the atmosphere, completely throughthe web, or partially through each, thereby allowing sensors, 74 and74', to read precisely the lateral position of each web. The preferredguidance system is the Model A9H manufactured by FIFE Corporation.

Since it has been determined that flexible web 56 tends to retain itslateral position, it is preferable to adjust the lateral position ofprecursor image web 34 to laterally align lenticular lens web 36 andprecursor image web 34 prior to laminating them into single graphicimage web 32. To obtain this lateral registry, the sensors, 74 and 74',supply an output signal to a controller which, in turn, provides outputsignals which control a guide roller assembly 76. Guide roller assembly76 is preferably hydraulically controlled to adjust the position ofprecursor image web 34 in the lateral direction. Such guide rollassemblies are commonly known and used in the printing industry.

Other types of guidance systems may also be used to provide preciselateral registry of the webs. For example, a laser guidance system whichuses a laser beam to track the edge of each web may be used.Additionally, a stylus guidance system could be used. In such a stylusguidance system, a stylus cooperates with a sensor to track a ridge or agroove disposed along the edge of the web, preferably the lenticule lensweb. It is important to note that with any of these guidance systems,the groove, ridge, or edge being tracked must be straight so that thewebs can be accurately registered and combined.

In the embodiment illustrated, the precursor image web 34 is slaved tothe lenticular lens web 36. However, registration assembly 50 could beconnected to slave the lenticular lens web 36 to precursor image web 34.In either case, the lateral registration of webs 34 and 36 occurs duringthe translation of each web prior to laminating webs 34 and 36 to formgraphic image web 32. This process allows efficient production ofcommercially viable lengths of graphic image web 32 when precise lateralregistration is required.

To facilitate efficient production of graphic image web 32, lenticularlens web 36 is created during the translation of flexible web 56 throughweb apparatus 30. As shown generally in FIG. 5, lenticule formingstation 70 comprises a coating roll 77 around which flexible web 56translates in an accurate path. Flexible web 56 includes an innersurface 78 which is later adhered to the 3-D printed side (i.e., theimage side) 40 of precursor image web 34. Flexible web 56 also includesa receiving surface 80 on which flowable curable resin 58 is deposited.Flowable resin 58 may be applied directly to receiving surface 80, butin a preferred embodiment, resin 58 is applied to coating roll 77 whichthen rotates into cooperation with receiving surface 80 as showngenerally in FIG. 4. Flowable resin 58 is applied by an applicator 82which creates a reservoir 84 of flowable resin 58 on the surface ofcoating roll 77. However, other methods of applying flowable resin, suchas spraying it onto coating roll 77, may be used without departing fromthe scope of the invention.

As flexible web 56 moves into lenticule forming station 70 it is routedaround a tension nip roller 86 and then into contact with coating roll77 in close proximity and on the downstream side of applicator 82. Thus,reservoir 84 is held between nip roller 86 and coating roll 77 so thatreceiving surface 80 of flexible web 56 is uniformly wetted with theflowable resin 58. Once surface 80 is wetted, the desired opticalsurface pattern is formed in the flowable resin on flexible web 56.

Coating roll 77 is relief cut in a pre-defined optical surface pattern.This optical surface pattern is preferably a recessed pattern oflenticules which imparts a convex lenticular pattern to the flowableresin 58. This desired pattern is maintained as flexible web 56 movesthrough lenticule forming station 70 and is cured prior to any levelingwhich would materially impair the desired lenticular pattern. Thelenticular pattern is maintained by holding flexible web 56 in contactwith coating roll 77 until it moves into proximity with a tension roller88 disposed downstream of coating roll 77. In the preferred embodiment,flowable resin 58 is a UV curable resin and is cured before flexible web56 moves out of contact with coating roll 77. A plurality of UVradiators 90 are disposed about coating roll 77 in such a manner thatthe UV rays are directed through the base of transparent flexible web 56and into resin 58 while it is maintained in the desired lenticularpattern against relief cut coating roll 77.

The relief cut pattern extends in an accurate path around thecircumference of coating roll 77. Preferably, the pattern is a screwpattern wherein one continuous relief cut groove, corresponding to thedesired physical shape of each lenticule, continually wraps around thecoating roll 77 similar to the thread of a screw. Thus, the relief cutgroove has a given pitch angle dependent on the size of the groove andthe diameter of coating roll 77. Such a continuous groove requires acoating roll 77 of sufficient size so that the pitch of the groove isnegligible. This ensures that the lenticular pattern formed in flowableresin 58 is nearly linearly aligned with the machine direction oflenticular lens web 36.

Roll 77 is relief cut to correspond to the desired number and thedesired shape of lenticules 60 both of which can vary substantiallydepending on various image web manufacturing parameters and desiredthree dimensional effect. To obtain a thin image web 32, it is desirableto have 100 or more lenticules per inch and preferably over 300lenticules per inch so that the convex lenticule has a short focallength and the thickness of lenticular lens web 36 is minimized. Asmentioned above, a higher density of lenticules reduces or eveneliminates the need for lateral registration 50.

The preferred shape of lenticules 60 is of a half cylinder splitlongitudinally, as shown generally in FIG. 8. However, the shape of thelenticule can be adjusted to facilitate shorter focal lengths withouthaving as great a multiplicity of lenticules per inch. Each lenticulecan be formed with greater curvature at its apex than throughout theremainder of the lenticule to provide a shorter focal length with abroader overall lenticule cross section. An example of such a lenticuleis one having a hyperbolic cross section.

To obtain optical alignment for the greatest three dimensional effect,the images on precursor image web 34 are tilted slightly with respect tothe machine direction of web 34. The tilt of the images corresponds tothe pitch of lenticules 60 so that image elements 26 are linearlyaligned with lenticules 60. In the preferred embodiment, the tiltedimages are created on precursor image web 34 with a web offset press,although other types of presses such as gravure or flexographic pressescan also be used.

A web offset press uses a printing unit 92 shown schematically in FIG.5. Ink is applied to an image carrier, such as a plate 94, which wrapsaround a plating cylinder 96. Plate 94 is etched with the desired imageand transfers the ink held by the etched image to a blanket cylinder 98which, in turn, transfers the image to precursor image web 34. Imagesmay be printed on both sides of precursor image web 34 simultaneously,as shown in FIG. 5. Usually, a series of printing units 92 is requiredsince only a single color will be applied at each printing unit 92.

To obtain optical alignment, the images are printed on precursor imageweb 34 at an angle which matches the pitch angle of the screw threads oncoating roll 77. This is preferably accomplished by one of two differentmethods. According to one method, plating cylinder 96 is cocked orrotated so that it is no longer perpendicular to the machine directionof precursor image web 34. The angle of rotation from perpendicularapproximately matches the pitch angle imparted to lenticules 60.Accordingly, the cocked plating cylinder 96 transfers the image toblanket cylinder 98 at the desired angle and blanket cylinder 98transfers the image to precursor image web 34 at the same angle so thatimage elements 26 and lenticules 60 will be linearly aligned whengraphic image web 34 and lenticular lens web 36 are combined.

According to the second method, the images are etched on plate 94 at thedesired pitch angle as shown in FIG. 6. Plate 94 includes an axis 100which is aligned with the machine direction of precursor image web 34.However, when an image 102 is etched in plate 94, it is oriented at anangle with respect to axis 100. This angle corresponds approximatelywith the pitch angle of the recessed screw threads on coating roll 77.Thus, like before, as precursor image web 34 is laminated to lenticularlens web 36, lenticules 60 will be linearly aligned with image elements26.

Following the curing of flowable resin 58 and the formation oflenticular lens web 36, lenticular lens web 36 moves around guide rolls72 and into contact with precursor image web 34 where it is adhered toprecursor image web 34 to form graphic image web 32 as described above.As shown generally in FIG. 7, graphic image web 32 typically comprises alayer of printing paper 106 on which are printed the image elements 26creating a printing layer 108. A layer of relatively transparentadhesive 48 is disposed on printing layer 108 and secures inner surface78 of flexible web 56 to precursor image web 34 (which includes paper106 and printing layer 108). A pre-defined topography 110 is formed fromcurable resin 58 and disposed on receiving surface 80 of flexible web56. In the preferred embodiment, the pre-defined topography 110 isformed in a pattern of lenticules 60 having the desired configurationand optical qualities so that when image elements 26 are viewed throughlenticules 60 and flexible web 56, the illusion of three dimensionalityis created. In this respect, it is desirable that each lenticule be ofgenerally the same width as each image element 26 and that eachlenticule 60 has a focal length which coincides with its distance fromprinting layer 108.

Numerous materials may be used to create the various layers which arecombined to form graphic image web 32. For example, flexible web 56 andlenticules 60 may be made from polycarbonate and laminated to apolycarbonate precursor image web 34. In another situation, it may beadvantageous to use Tyvek, a material manufactured by the DuPontCompany, as the precursor image web. A wide variety of materialsincluding synthetics and nonsynthetics, those with woven or nonwovenfibers, and those with oriented or nonoriented fibers may be used toform one or more of the precursor image web 34, flexible web 56, orlenticules 60.

It will be understood that the foregoing description is of a preferredexemplary embodiment of this invention, and that the invention is notlimited to the specific form shown. For example, the lenticules may beof different shape or size, different types of curable resin may beused, and the arrangement of various components in web apparatus may bechanged. These and other modifications may be made in the design andarrangement of the elements without departing from the scope of theinvention as expressed in the appended claims.

What is claimed is:
 1. A method for forming a graphic image webincluding a precursor image web combined with a congruent lenticularlens web to produce the illusion of three dimensionality in a visuallyperceptible image on said graphic image web, said method comprising thesteps of:defining an image field including an object to be viewed;imagewise exposing said object onto a photographically sensitive elementover a plurality of spatially disparate views through a lenticular lenshaving a prescribed optical geometry; developing the latent image onsaid element; printing the developed image to form said precursor imageweb; and optically combining said congruent lenticular lens web withsaid precursor image web to create said graphic image web having graphicinformation of photographically acceptable quality imparted with theillusion of three dimensionality.
 2. The method of claim 1, furthercomprising the step of optically aligning said precursor image web andsaid lenticular lens web.
 3. The method of claim 2, wherein saidaligning step is accomplished during translation of said precursor imageweb and said lenticular lens web.
 4. The method of claim 1, wherein saidlenticular lens web has a plurality of lenticules.
 5. The method ofclaim 4, wherein said step of imagewise exposing said object throughsaid lenticular lens over said plurality of spatially disparate viewscreates a plurality of image elements on said photographically sensitivemember, each image element being defined by a plurality of condensedimage bands, each image band representing a particular spatiallydisparate view, and further wherein said plurality of image elements aredeveloped on said photographically sensitive member and printed ontosaid web.
 6. The method of claim 5, wherein said step of imagewiseexposing said object is over an infinite number of spatially disparateviews to create uninterrupted image elements, each image element beingdefined by an infinite number of said image bands.
 7. The method ofclaim 5, wherein the step of printing the developed image is replicatedalong the length of said precursor image web.
 8. The method of claim 7,wherein the step of optically combining said webs comprises the step oflaminating a congruent lenticular lens web, having a multiplicity oflenticules, to said precursor image web to create a graphic image webhaving three dimensionality.
 9. The method of claim 8, furthercomprising the step of axially aligning said image elements on saidprecursor image web with said lenticules of said lenticular lens web sosaid lenticules are disposed generally over said image elements in aone-to-one relationship.
 10. The method of claim 6, further comprisingthe steps of applying an adhesive over the developed image on saidprecursor image web and pressing said precursor image web against saidlenticular lens web, wherein said adhesive binds said precursor imageweb to said lenticular lens web.
 11. A method for forming a graphicimage web including a precursor image web for combination with alenticular lens web to produce the illusion of three dimensionality in avisually perceptible image on said graphic image web, said methodcomprising the steps of:defining an image field including an object tobe viewed; imagewise exposing said object onto a photographicallysensitive element over a plurality of spatially disparate views througha lenticular lens having a prescribed optical geometry to create aplurality of image elements; developing the latent image on saidphotographically sensitive element; printing the developed imagerepetitively along a web to form said precursor image web; forming aplurality of lenticules on a flexible web to create said lenticular lensweb, said forming step being accomplished while said flexible web istranslating in a machine direction; and optically combining saidlenticular lens web with said precursor image web to create a graphicimage web having graphic information of photographically acceptablequality imparted with the illusion of three dimensionality.
 12. Themethod of claim 11, wherein said lenticules are oriented at a pitchangle to said machine direction.
 13. The method of claim 12, whereinsaid image elements are oriented to fall into linear alignment with saidlenticules when said precursor image web is optically combined with saidlenticular lens web.
 14. The method of claim 13, wherein said precursorimage web and said lenticular lens web are translating during said stepof optically combining.
 15. The method of claim 14, wherein said step offorming a plurality of lenticules includes applying a curable resin tosaid flexible web, impressing said resin by translating said flexibleweb around a coating roll having a relief cut lenticular pattern, andcuring said resin.
 16. The method of claim 15, wherein said coating rollincludes a relief cut screw pattern which impresses said resin to formlenticules oriented at said pitch angle to said machine direction.
 17. Amethod for producing a graphic image having the illusion ofthree-dimensionality by joining a precursor image with a superimposedlenticular film through which said precursor image is to be viewed, theimprovement comprising the step of web-fed lamination of a precursorimage web and a lenticular lens web to produce a graphic image web inwhich the perceptible image possesses photographically acceptablequality.
 18. The method of claim 17, wherein said lenticular lens webincludes lenticules of sufficient density to produce said graphic imageweb in which the perceptible image possesses photographically acceptablequality.
 19. The method of claim 17, wherein a registration assemblylaterally aligns said lenticular lens web with said precursor image webto produce said graphic image web in which the perceptible imagepossesses photographically acceptable quality.
 20. The method of claim17, wherein said step of web-fed lamination occurs during translation ofsaid precursor image web and said lenticular lens web.